Comparative Studies on the Ablation/Erosion Mechanisms of Silicone Rubber Composites under Erosion of Different Particles by New Testing Method

Abstract The performance of solid rocket ramjets is affected by the ablation resistance of silicone rubber composites in the secondary combustion chamber. To investigate the ablation mechanisms of silicone rubber composites in multiphase flow environments, a new ablation testing methodology, in which particles can be added to the flame, is developed in this investigation. Boron oxide (B2O3) and alumina (Al2O3) particles were used to simulate condensed-phase particles. The experimental results show that because of the high hardness and melting point of Al2O3, the mechanical destruction of the Al2O3 particles was so intense that the surface of silicone rubber composite was completely destroyed, and the matrix was exposed to the surface. The surfaces of the B2O3 particles melted and evaporated in the flame, forming a liquid layer, similar to condensed-phase particles in the secondary combustion chamber of solid ramjet. After the ablation of silicone rubber under the erosion action of B2O3 particles, a char layer and pyrolysis layer were formed, similar to the scenario during the actual ablation of silicone rubber composites. The multiphase flow environment with B2O3 particles can truly reflect the ablative environment experienced by silicone rubber composites.